Programmable mutlistage amplifier and radio applications thereof

ABSTRACT

A programmable multi-stage amplifier includes a 1 st  programmable amplifier, a 2 nd  programmable amplifier, and a control module. The 1 st  and 2 nd  programmable amplifiers are coupled in series to amplify an input signal. Each of the 1 st  and 2 nd  programmable amplifiers is operably coupled to receive independent gain control signals from the control module. The control module generates the gain control signals by determining the overall gain desired for the programmable multi-stage amplifier and a corresponding gain for each of the 1 st  and 2 nd  programmable amplifiers. The factors in which the control module makes this determination are based on an optimization of at least one of the power level of the programmable multi-stage amplifier, the noise factor for the programmable multi-stage amplifier, and/or linearity of the programmable multi-stage amplifier.

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates generally to communication systems andmore particularly to radio transceivers used within such communicationsystems.

BACKGROUND OF THE INVENTION

[0002] Communication systems are known to support wireless and wirelined communications between wireless and/or wire lined communicationdevices. Such communication systems range from national and/orinternational cellular telephone systems to the Internet topoint-to-point in-home wireless networks. Each type of communicationsystem is constructed, and hence operates, in accordance with one ormore communication standards. For instance, wireless communicationsystems may operate in accordance with one or more standards including,but not limited to, IEEE 802.11, Bluetooth, advanced mobile phoneservices (AMPS), digital AMPS, global system for mobile communications(GSM), code division multiple access (CDMA), wireless applicationprotocols (WAP), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

[0003] Depending on the type of wireless communication system, awireless communication device, such as a cellular telephone, two-wayradio, personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel (e.g., one of the plurality of radiofrequency (RF) carriers of the wireless communication system) and shareinformation over that channel. For indirect wireless communications,each wireless communication device communicates directly with anassociated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe internet, and/or via some other wide area network.

[0004] For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver receives RFsignals, removes the RF carrier frequency from the RF signals via one ormore intermediate frequency stages, and demodulates the signals inaccordance with a particular wireless communication standard torecapture the transmitted data. The transmitter converts data into RFsignals by modulating the data in accordance with the particularwireless communication standard and adds an RF carrier to the modulateddata in one or more intermediate frequency stages to produce the RFsignals.

[0005] As the demand for enhanced performance (e.g., reducedinterference and/or noise, improved quality of service, compliance withmultiple standards, increased broadband applications, et cetera),smaller sizes, lower power consumption, and reduced costs increases,wireless communication device engineers are faced with a very difficultdesign challenge to develop such a wireless communication device.Typically, an engineer is forced to compromise one or more of thesedemands to adequately meet the others. For instance, an engineer maychoose a direct conversion topology (i.e., convert directly from an RFsignal to a base-band signal or directly from a base-band signal to anRF signal) to meet size requirements and/or broadband applicationrequirements. However, for direct conversion transceivers, noise and/orinterference increases due to local oscillation leakage, non-linearitiesdue to component mismatches and/or process variations are moredetrimental to overall performance, and DC offsets, which result from aslight offset between the transmitting frequency of one wirelesscommunication device and the frequency of the receiver in anotherwireless communication device, are more pronounced.

[0006] As is known, local oscillation leakage results from imperfectionsof the mixers within a transmitter that allow the local oscillation,which equals the RF, to be present in the resultant RF signal. The localoscillation leakage can be minimized by using multiple IF stages withinthe transmitter. In such an implementation, each IF stage uses a localoscillation that has a significantly different frequency than the RF,with the sum of the multiple local oscillations equals the RF. Sinceeach local oscillation has a significantly different frequency than theRF, each local oscillation is outside the RF band of interest (i.e., thefrequency spectrum of the resulting RF signal). But this requires anabandoning of the direct conversion topology and its benefits withrespect to size reduction, power consumption reduction, reduced costs,and reduced complexity for broadband applications.

[0007] Costs of manufacturing a radio frequency integrated circuit (IC)may be reduced by switching from one integrated circuit manufacturingprocess to another. For example, a CMOS process may be used instead of abi-CMOS process since it is a more cost affective method of ICmanufacture, but the CMOS process increases component mismatches,increases temperature related variations, and increases processvariations. As such, noise, local oscillator leakage, non-linearitiesand other factors that negatively impact an RF IC performance areincreased for a CMOS process. Thus, in many RF IC applications, adesigner chooses between cost savings and performance.

[0008] As is further known, many wireless communication standardsprovide for varying the transmitting power of the transmitter based onreceived signal strength of the wireless communication device receivingthe transmission to conserve power. For instance, if the received RFsignal is very strong, the receiver can easily recapture the embeddeddata. In such an instance, the transmission power level of thetransmitter can be reduced and still provide a sufficiently strong RFsignal to enable the receiver accurately recover the embedded data.Conversely, when the received signal is too weak, the receiver cannotaccurately recover the embedded data, thus the transmission power levelneeds to be increased. Typically, the transmitter power is increased byincreasing the gain of its power amplifier. The gain of the poweramplifier is increased by changing the bias level of the input signal.While this increases the gain, the linearity of the power amplifier isadversely affected, which adversely affects the performance of thetransmitter and the overall radio.

[0009] Therefore, a need exists for a low power, reduced size, reducedcost, and enhanced performance radio, radio transmitter, radio receiver,and/or components thereof.

SUMMARY OF THE INVENTION

[0010] These needs and others are substantially met by the programmablemulti-stage amplifier and radio applications thereof disclosed herein.In one embodiment, the programmable multi-stage amplifier includes a1^(st) programmable amplifier, a 2^(nd) programmable amplifier, and acontrol module. The 1^(st) and 2^(nd) programmable amplifiers arecoupled in series to amplify an input signal. Each of the 1^(st) and2^(nd) programmable amplifiers is operably coupled to receiveindependent gain control signals from the control module. The controlmodule generates the gain control signals by determining the overalldesired gain for the programmable multi-stage amplifier and acorresponding gain for each of the 1^(st) and 2^(nd) programmableamplifiers. The factors in which the control module makes thisdetermination are based on an optimization of at least one of the powerlevel of the programmable multi-stage amplifier, the noise factor forthe programmable multi-stage amplifier, and/or linearity of theprogrammable multi-stage amplifier.

[0011] The programmable multi-stage amplifier may be incorporated into aradio transmitter, which may be a stand-alone device and/or incorporatedinto a radio. By incorporating a multi-stage amplifier in a transmitterand/or radio, linearity, noise level and/or power levels may be improvedfor the transmitter and thus improve for the overall radio.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 illustrates a schematic block diagram of a communicationsystem that supports wireless communication devices in accordance withthe present invention;

[0013]FIG. 2 illustrates a schematic block diagram of a wirelesscommunication device in accordance with the present invention;

[0014]FIG. 3 illustrates a schematic block diagram of a transmitter inaccordance with the present invention;

[0015]FIG. 4 illustrates a logic diagram of a method for determininggain of a programmable multi-stage amplifier based on a desired powerlevel in accordance with the present invention;

[0016]FIG. 5 illustrates a logic diagram of a method for determininggain of a programmable multi-stage amplifier based on a desired noiselevel in accordance with the present invention;

[0017]FIG. 6 illustrates a logic diagram of a method for determininggain based on linearity of a multi-stage power amplifier in accordancewith the present invention;

[0018]FIG. 7 illustrates a logic diagram of a method for balancing gainof a programmable multi-stage amplifier based on a desired noise level,desired output power and desired linearity in accordance with thepresent invention;

[0019]FIG. 8 illustrates a schematic block diagram of an alternatetransmitter in accordance with the present invention; and

[0020]FIG. 9 illustrates a schematic block diagram of multi-embodimentsof a highly linear power amplifier in accordance with the presentinvention.

DETAIL DESCRIPTION OF A PREFERRED EMBODIMENT

[0021]FIG. 1 illustrates a schematic block diagram of a communicationsystem 10 that includes a plurality of base stations and/or accesspoints 12-16, a plurality of wireless communication devices 18-32 and anetwork hardware component 34. The wireless communication devices 18-32may be laptop host computers 18 and 26, personal digital assistant hosts20 and 30, personal computer hosts 24 and 32 and/or cellular telephonehosts 22 and 28. The details of the wireless communication devices willbe described in greater detail with reference to FIG. 2.

[0022] The base stations or access points 12 are operably coupled to thenetwork hardware 34 via local area network connections 36, 38 and 40.The network hardware 34, which may be a router, switch, bridge, modem,system controller, et cetera provides a wide area network connection 42for the communication system 10. Each of the base stations or accesspoints 12-16 has an associated antenna or antenna array to communicatewith the wireless communication devices in its area. Typically, thewireless communication devices register with a particular base stationor access point 12-14 to receive services from the communication system10. For direct connections (i.e., point-to-point communications),wireless communication devices communicate directly via an allocatedchannel.

[0023] Typically, base stations are used for cellular telephone systemsand like-type systems, while access points are used for in-home orin-building wireless networks. Regardless of the particular type ofcommunication system, each wireless communication device includes abuilt-in radio and/or is coupled to a radio. The radio includes a highlylinear amplifier and/or programmable multi-stage amplifier as disclosedherein to enhance performance, reduce costs, reduce size, and/or enhancebroadband applications.

[0024]FIG. 2 illustrates a schematic block diagram of a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component.

[0025] As illustrated, the host device 18-32 includes a processingmodule 50, memory 52, radio interface 54, input interface 58 and outputinterface 56. The processing module 50 and memory 52 execute thecorresponding instructions that are typically done by the host device.For example, for a cellular telephone host device, the processing module50 performs the corresponding communication functions in accordance witha particular cellular telephone standard.

[0026] The radio interface 54 allows data to be received from and sentto the radio 60. For data received from the radio 60 (e.g., inbounddata), the radio interface 54 provides the data to the processing module50 for further processing and/or routing to the output interface 56. Theoutput interface 56 provides connectivity to an output display devicesuch as a display, monitor, speakers, et cetera such that the receiveddata may be displayed. The radio interface 54 also provides data fromthe processing module 50 to the radio 60. The processing module 50 mayreceive the outbound data from an input device such as a keyboard,keypad, microphone, et cetera via the input interface 58 or generate thedata itself. For data received via the input interface 58, theprocessing module 50 may perform a corresponding host function on thedata and/or route it to the radio 60 via the radio interface 54.

[0027] Radio 60 includes a host interface 62, digital receiverprocessing module 64, analog-to-digital converter 66, filtering/gainmodule 68, down conversion module 70, low noise amplifier 72, localoscillation module 74, memory 75, digital transmitter processing module76, digital-to-analog converter 78, filtering/gain module 80,up-conversion module 82, power amplifier 84, and an antenna 86. Theantenna 86 may be a single antenna that is shared by the transmit andreceive paths or may include separate antennas for the transmit path andreceive path. The antenna implementation will depend on the particularstandard to which the wireless communication device is compliant.

[0028] The digital receiver processing module 64 and the digitaltransmitter processing module 76, in combination with operationalinstructions stored in memory 75, execute digital receiver functions anddigital transmitter functions, respectively. The digital receiverfunctions include, but are not limited to, digital intermediatefrequency to baseband conversion, demodulation, constellation demapping,decoding, and/or descrambling. The digital transmitter functionsinclude, but are not limited to, scrambling, encoding, constellationmapping, modulation, and/or digital baseband to IF conversion. Thedigital receiver and transmitter processing modules 64 and 76 may beimplemented using a shared processing device, individual processingdevices, or a plurality of processing devices. Such a processing devicemay be a microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. The memory 75may be a single memory device or a plurality of memory devices. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the processing module 64 and/or 76 implements one or more of itsfunctions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory storing the corresponding operationalinstructions is embedded with the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.The memory 75 stores, and the processing module 64 and/or 76 executes,operational instructions corresponding to at least some of the functionsillustrated in FIGS. 3-8.

[0029] In operation, the radio 60 receives outbound data 94 from thehost device via the host interface 62. The host interface 62 routes theoutbound data 94 to the digital transmitter processing module 76, whichprocesses the outbound data 94 in accordance with a particular wirelesscommunication standard (e.g., IEEE802.11a, IEEE802.11b, Bluetooth, etcetera) to produce digital transmission formatted data 96. The digitaltransmission formatted data 96 will be a digital base-band signal or adigital low IF signal, where the low IF will be in the frequency rangeof zero to a few megahertz.

[0030] The digital-to-analog converter 78 converts the digitaltransmission formatted data 96 from the digital domain to the analogdomain. The filtering/gain module 80 filters and/or adjusts the gain ofthe analog signal prior to providing it to the up-conversion module 82.The up-conversion module 82 directly converts the analog baseband or lowIF signal into an RF signal based on a transmitter local oscillationprovided by local oscillation module 74. The power amplifier 84, whichmay include the highly linear power amplifier discussed in FIG. 9 and/orthe programmable power amplifier discussed in FIGS. 3-7, amplifies theRF signal to produce outbound RF signal 98. The antenna 86 transmits theoutbound RF signal 98 to a targeted device such as a base station, anaccess point and/or another wireless communication device.

[0031] The radio 60 also receives an inbound RF signal 88 via theantenna 86, which was transmitted by a base station, an access point, oranother wireless communication device. The antenna 86 provides theinbound RF signal 88 to the low noise amplifier 72, which amplifies thesignal 88 to produce an amplified inbound RF signal. The low noiseamplifier 72 provide the amplified inbound RF signal to the downconversion module 70, which directly converts the amplified inbound RFsignal into an inbound low IF signal based on a receiver localoscillation provided by local oscillation module 74. The down conversionmodule 70 provides the inbound low IF signal to the filtering/gainmodule 68, which filters and/or adjusts the gain of the signal beforeproviding it to the analog to digital converter 66.

[0032] The analog-to-digital converter 66 converts the filtered inboundlow IF signal from the analog domain to the digital domain to producedigital reception formatted data 90. The digital receiver processingmodule 64 decodes, descrambles, demaps, and/or demodulates the digitalreception formatted data 90 to recapture inbound data 92 in accordancewith the particular wireless communication standard being implemented byradio 60. The host interface 62 provides the recaptured inbound data 92to the host device 18-32 via the radio interface 54.

[0033]FIG. 3 illustrates a more detailed schematic block diagram of atransmitter 100 that may be used in radio 60. In this embodiment, thedigital transmitter processing module 70 includes multiplexors 103 and105 and control module 104. The power amplifier 84 is implementedutilizing a programmable multi-stage amplifier 101 that includes a1^(st) programmable amplifier 106 and a 2^(nd) programmable amplifier108. The transmitter 100 also includes a power detector 110 thatdetermines the output power of the outbound RF signal 98 utilizing atransmitter signal strength indication and/or any other technique fordetermining output power levels of RF signals. As one of average skillin the art will appreciate, the programmable multi-stage amplifier 101may include more than two programmable amplifiers.

[0034] During normal operation, the control module enables multiplexors103 and 105 to pass the I and Q components of outbound data 94 to thedigital-to-analog converter 78. The digital-to-analog converter 78converts the I and Q components of the digital transmission formatteddata 96 into corresponding analog signals. The filtering/gain module 80converts the analog transmission formatted data into a low IF signal114, which has an intermediate frequency ranging from zero Hertz to afew megahertz. The up-conversion module 82, based on a transmitter localoscillation provided by the local oscillator module 74, converts the lowIF signal 114 into an RF signal 116.

[0035] The power amplifier 84, via the programmable multi-stageamplifier 101 amplifies the RF signal 116, based on a distributed gaincontrol signal 122, to produce the outbound RF signal 98. Thedistributed gain control signal 122 provides a gain control signal tothe 1^(st) programmable amplifier 106 and a gain control signal to the2^(nd) programmable amplifier 108. Note that the 1^(st) and/or 2^(nd)programmable amplifiers 106 and/or 108 may be implemented in accordancewith the highly linear power amplifier illustrated in FIG. 9.

[0036] To determine the distributed gain control signal 122, the controlmodule 104 places the transmitter 100 in a test mode by enablingmultiplexors 103 and 105 to respectively output an I and Q component ofa test signal 120. During test mode, the digital-to-analog converter 78converts the I and Q components of the test signal 120 intocorresponding analog signals, which are subsequently filtered and/orgain adjusted by the filtering and gain module 80. The up-conversionmodule 82 converts the analog representation of the test signal 120 intoa test RF signal based on the transmitter local oscillation. The poweramplifier 84, via the programmable multi-stage amplifier 101 amplifiesthe RF test signal to produce an outbound RF test signal. The powerdetector 110 detects the power level of the outbound RF test signal andprovides it back to the control module 104. Depending on what aspect thecontrol module is currently testing (i.e., for noise level, linearity,or power levels), the control module determines whether the currentsetting for the gain of the 1^(st) programmable amplifier and 2^(nd)programmable amplifier 108 meets the desired limits. If so, the controlmodule 104 switches back to normal operating mode by enabling themultiplexors 103 and 105 to pass the I and Q components of the outbounddata 94.

[0037] If, however, the current gain settings for the 1^(st) and 2^(nd)programmable amplifiers 106 and 108 do not produce an output within thedesired performance levels, the control module 104 changes thedistributed gain control signal thus changing the gain of the 1^(st)and/or 2^(nd) programmable amplifiers. Having changed the gain, thecontrol module 104 again provides test signal 120 to the transmitter andagain determines its output power for this signal. This processcontinues until the outbound RF test signal is within the desiredparameters.

[0038]FIG. 4 illustrates a logic diagram of a method for establishing adesired power level setting for the programmable multi-stage amplifier101 which may be executed by control module 104. The process begins atStep 130 where the control module generates a test signal to test for adesired power level setting of the programmable multi-stage amplifier.The process then proceeds to Step 132 where the control module providesan I component and a Q component of the test signal to the up-conversionmodule. The up-conversion module produces an RF test signal that isamplified by the programmable multi-stage amplifier to produce anoutbound RF test signal.

[0039] The process then proceeds to Step 134 where the control moduledetermines output power of the outbound RF test signal. The process thenproceeds to Step 136 where the control module determines whether theoutput power of the outbound RF test signal is within a desired outputpower range. For instance, depending on the mode of operation, theoutput power may be in a power conservation mode, sleep mode, or maxpower mode, and/or any other mode of operation that would affect theoutput level of the transmitter. If the output power is within thedesired output range, the process proceeds to Step 140 where thedistributed gain control signal is established to set the gain of theprogrammable multi-stage amplifier to maintain the output power in thedesired range. In many instances, the gain will remain as set for thecurrent test.

[0040] If, however, the output power of the outbound RF test signal isnot within the desired output power range, the process proceeds to Step138. At Step 138, the control module adjusts the distributed gaincontrol signal (i.e., adjust the gain provided to the 1^(st) and/or2^(nd) programmable amplifiers) to produce an adjusted distributed gaincontrol signal. At this point, the process reverts back to Step 130 andrepeats until the output power of the outbound RF test signal is withina desired output power range.

[0041]FIG. 5 illustrates a logic diagram of a method for determiningnoise level for the programmable multi-stage amplifier, which may beexecuted by control module 104. The process begins at Step 150 where thecontrol module generates a test signal to test for noise level of theprogrammable multi-stage amplifier. The process then proceeds to Step152 where the control module provides an I and Q component of the testsignal to the up-conversion module. The up-conversion module convertsthe I and Q components of the test signal based on a local oscillationto produce an RF test signal. The programmable multi-stage amplifieramplifies the RF test signal to produce an outbound RF test signal.

[0042] The process then proceeds to Step 154 where the control moduledetermines the noise level of the outbound RF test signal. The processthen proceeds to Step 156 where the control module determines whetherthe noise level of the outbound RF test signal is below a desired noiselevel. If so, the process proceeds to Step 160 where the control moduleestablishes the distributed gain control signal to set the gain of theprogrammable multi-stage amplifier such that the noise level is belowthe desired noise level.

[0043] If, however, the noise level of the outbound RF test signal isnot below the desired noise level, the process proceeds to Step 158. AtStep 158, the control level adjusts the distributed gain control signal(i.e., changes the gain control signal provided to the 1^(st) and/or2^(nd) programmable amplifier) to produce an adjusted distributed gaincontrol signal. The process then reverts back to Step 150 where theprocess repeats until the noise level of the outbound RF test signal isbelow a desired noise level. Note that the test signal may be a zerosignal wherein all outputted signals is representative noise, the testsignal may be a test signal having a fixed frequency and fixed amplitudesuch that any deviation therefrom is reflective of noise, and/or anyother type of signal such that noise can be readily distinguished fromthe signal. As one of average skill in the art will appreciate, thenoise level may be detected by a signal-to-noise ratio, and/or any othermechanism for measuring noise components of a signal.

[0044]FIG. 6 illustrates a logic diagram of a method that may beexecuted by the control module 104 to determine linearity of theprogrammable multi-stage amplifier. The process begins at Step 170 wherethe control module generates a series of varying power level testsignals to test the linearity of the programmable multi-stage amplifier.The process then proceeds to Step 172 where the control modulesequentially provides the series of varying power level test signals tothe up-conversion module. The up-conversion module converts each of thetest signals into RF test signals, which are subsequently amplified bythe programmable multi-stage amplifier to produce a plurality ofoutbound RF test signals.

[0045] The process then proceeds to Step 174 where the control moduledetermines output power for each of the series of outbound RF testsignals. The process then proceeds to Step 176 where the control moduledetermines linearity of the programmable multi-stage amplifier based onthe output power of the series of output RF test signals. For instance,if the programmable multi-stage amplifier is linear, the ratio betweenthe input power and output power for each of the test signals should bethe same, within reasonable engineering tolerances.

[0046] The process then proceeds to Step 178 where the control moduledetermines whether the linearity of the programmable multi-stageamplifier is within a desired linearity range. If so, the processproceeds to Step 180 where the control module establishes thedistributed gain control signal to set the gain of the programmablemulti-stage amplifier such that the linearity is within the desiredrange. Typically, this entails setting the gain for the 1^(st) and/or2^(nd) programmable amplifiers at the gain used when the linearity wasdetermined to be within the desired range.

[0047] If, however, the linearity of the programmable multi-stageamplifier is not within a desired linearity range, the process proceedsto Step 182. At Step 182, the control module adjusts the distributedgain control signal to produce an adjusted distributed gain controlsignal. As such, the control module is adjusting the gain of the 1^(st)and/or 2^(nd) programmable amplifier. At this point, the process repeatsat Step 170 until the linearity of the programmable multi-stageamplifier is within the desired linearity range.

[0048]FIG. 7 illustrates a logic diagram of a method that may beimplemented by the control module to balance the distributed gainsetting signal for power levels, linearity and/or noise. The processbegins at Step 90 where the control module determines a 1^(st) optimalsetting or the distributed gain control signal such that the noise levelof the programmable multi-stage amplifier is below the desired noiselevel. This may be done as discussed with reference to FIG. 5. Theprocess then proceeds to Step 192 where the control module determines a2^(nd) optimal setting for the distributed gain control signal such thatthe output power of the programmable multi-stage amplifier is within adesired output power range. This may be done in accordance with theprocess illustrated in FIG. 4. The process then proceeds to Step 194where the control module determines a 3^(rd) optimal setting for thedistributed gain control signal such that the linearity of theprogrammable multi-stage amplifier is within a desired linearity range.This may be done as described in FIG. 6.

[0049] The process then proceeds to Step 196 where the control moduletests the linearity, noise, and power level using each of the 1^(st),2^(nd) and 3^(rd) optimal settings. As such, the control module,utilizing the 1^(st) optimal setting, tests the linearity and powerlevels to determine whether they are within the respective ranges.Similarly, the control module uses the 2^(nd) optimal setting todetermine whether the noise and linearity are at desired levels orwithin desired ranges. Also, the control module utilizing the 3^(rd)optimal setting to determine whether the power level and noise arewithin their respective ranges.

[0050] The process then proceeds to Step 198 where the control moduledetermines whether, for any of the 1^(st), 2^(nd) or 3^(rd) optimalsettings, the noise, the linearity and/or the power level is not withinits desired range and/or level. If the noise, linearity and power levelfor all three optimal settings are within their respective ranges, theprocess proceeds to Step 200. At Step 200, the control module uses one,or more in combination, of the 1^(st) 2^(nd) or 3^(rd) optimal settingfor the distributed gain control signal.

[0051] If, however, at Step 198, the response was negative, the processproceeds to Step 202. At Step 202, the control module adjusts thedistributed gain control signal based on prioritization of output power,noise level or linearity. Such a prioritization would be based on theparticular application and/or wireless communication standard beingimplemented by the radio. For example, noise and output power are ofgreater importance than linearity for a Bluetooth application.Conversely, linearity is a primary concern in an 802.11.a or .bapplication.

[0052] After adjusting the distributed gain control signal, the processreverts to Step 190. The processing continues until a distributed gaincontrol signal can be determined which satisfies the desired noise levelrequirements, desired output level requirements and the desiredlinearity requirements. If such an optimal setting cannot be obtained,one or more of the desired output power, noise level or linearity isadjusted to reach a compromised setting.

[0053]FIG. 8 illustrates a schematic block diagram of an alternatetransmitter 210 that may be utilized in radio 60. The transmitter 210includes the digital transmitter processing module 76, thedigital-to-analog converter 78, the filtering/gain module 80,up-conversion module 82, the power amplifier 84, and the power detector110. The digital transmitter processing module 76 is configured toinclude control module 104 and multiplexors 103 and 105. The poweramplifier 84 is implemented using highly linear power amplifier 212. Thegain of the highly linear power amplifier 212 may be adjusted inaccordance with enable signals 216 while having negligible effect on thelinearity of power amplifier 212. The details of power amplifier 212will be discussed in greater detail with reference to FIG. 9.

[0054] In operation, the control module 104 enables multiplexors 103 and105 to output an I and Q component of outbound data 94 to thedigital-to-analog converter 78. The digital-to-analog converter 78,filtering/gain module 80 and up-conversion module 82 perform aspreviously discussed. The highly linear power amplifier 212 amplifiesthe RF signal 116 at a particular gain setting, which is established viaenable signals 216 to produce the outbound RF signal 98.

[0055] To determine the enable signals 216, and thus the particular gainsetting for the highly linear power amplifier 212, the control module104 provides a test signal 214 to the transmitter 210. To do this, thecontrol module 104 enables multiplexors 103 and 105 to output an I and Qcomponent of test signal 214. The test signal 214 propagates through thetransmitter until an outbound RF test signal is produced. The powerdetector 110 detects the power level of this test signal and provides anindication back to control module 104. If the power level of the RF testsignal is at a desired level, the control module 104 utilizes thecurrent settings for enable signals 216.

[0056] If, however, the power level is not at the desired level, thecontrol module 104 adjusts the enable signals to change the gain of thehighly linear power amplifier 212. After making the gain adjustments,the control module 104 provides test signal 214 to transmitter 210. Thetest signal 214 is again propagated through transmitter 210 until itsoutput power is detected via power detector 110. This process continuesuntil the control module 104 determines that it has the proper settingsfor the gain of the highly linear power amplifier 212.

[0057]FIG. 9 illustrates a schematic block diagram of the highly linearpower amplifier 212. In this illustration, the highly linear poweramplifier 212 is a differential implementation. For a single implementedimplementation, the complimentary transistor pairs 230, 232 and 234 andcomponent 222 would be omitted.

[0058] The highly linear power amplifier 212, in a differential mode,includes 1^(st) and 2^(nd) components 220 and 222, which may beresistors, inductors and/or linearly loaded transistors and may furtherinclude a capacitor in parallel, a plurality of transistor pairs 224-228and a plurality of complimentary transistor pairs 230-234. Each of thetransistor pairs includes an enable transistor and an input transistor.The input transistors for the 1^(st), 2^(nd) and 3^(rd) transistor pairs224-226 are operably coupled to one leg of a differential input signal236. The input transistors of the 1^(st), 2^(nd) and 3^(rd)complimentary transistor pairs 230-234 are operably coupled to anotherleg of differential input signal 236. The enable transistors for the1^(st), 2^(nd) and 3^(rd) transistor pairs 224-228 are operably coupledto individual enable signals 244, 246 and 248. The enable transistors ofthe complimentary transistor pairs 230-234 are also individually coupledto the 1^(st), 2^(nd) and 3^(rd) enable signals 244-248.

[0059] By sizing the input transistors and corresponding enabletransistors of the transistor pairs with a given ratio with respect toeach other, the gain of the power amplifier 212 may be adjusted whilehaving negligible effects on the linearity. For instance, by having theinput transistor of the 1^(st) transistor pair being twice as big as theinput transistor of the 2^(nd) transistor pair, the gain of the 1^(st)transistor pair will be twice that of the 2^(nd) transistor pair. Yet,by matching the input transistors and enable transistors from pair topair, with only the size changing, the gain of the amplifier may bereadily changed with negligible affects on the amplifier's linearity.

[0060] As one of average skill in the art will appreciate, the 1^(st),2^(nd) and 3^(rd) enable signals may be enabled in any combination toproduce a desired gain for the power amplifier. As one of average skillin the art will further appreciate, the gain is cumulative astransistors are enabled within the power amplifier 212. As one ofaverage skill in the art will further appreciate, the linearity of thedevice remains relatively constant as the gain changes since the biaslevel for the input transistors of the transistor pairs is not varied.

[0061] The preceding discussion has presented a programmable multi-stageamplifier and a highly linear power amplifier that may be used in atransmitter of a radio. By providing programmability of such devices,the performance, cost and/or broadband applications of radios areenhanced. As one of average skill in the art will appreciate, theprogrammable multistage amplifier may be used in a variety ofapplications outside of radios, such as filters, speakers, etc. As oneof average skill in the art will further appreciate, other embodimentsmay be derived from the teaching of the present invention, withoutdeviating from the scope of the claims.

What is claimed is:
 1. A transmitter having a programmable amplifiercomprises: up-conversion module operably coupled to produce a radiofrequency (RF) signal from an I component of a low intermediatefrequency (IF) signal, Q component of the low IF signal, an I componentof a local oscillation, and a Q component of a local oscillation;programmable multistage amplifier operably coupled to amplify, based ona distributed gain control signal, the RF signal to produce an outboundRF signal; and control module operably coupled to generate thedistribute gain control signal based on an optimization of at least oneof: power level, noise factor, and linearity of the programmablemultistage amplifier.
 2. The transmitter of claim 1, wherein theprogrammable multistage amplifier comprises: first programmableamplifier operably coupled to produce an amplified RF signal byamplifying the RF signal in accordance with a first gain control signalof the distributed gain control signal; and second programmableamplifier operably coupled to produce the outbound RF signal byamplifying the amplified RF signal in accordance with a second gaincontrol signal of the distributed gain control signal.
 3. Thetransmitter of claim 1, wherein the control module further comprises:processing module; and memory operably coupled to the processing module,wherein the memory includes operational instructions that cause theprocessing module to: generate a test signal to test for a desired powerlevel setting of the programmable multistage amplifier; provide an Icomponent and a Q component of the test signal to the up-conversionmodule, wherein the up-conversion module produces an RF test signal thatis amplified by the programmable multistage amplifier to produce anoutbound RF test signal; determine output power of the outbound RF testsignal; determine whether the output power of the outbound RF testsignal is within a desired output power range; when the output power ofthe outbound RF test signal is not within the desired output powerrange, adjust the distributed gain control signal to produce an adjusteddistributed gain control signal; and repeat the providing the I and Qcomponents of the test signal, the determining the output power of theoutbound RF test signal with gain of the programmable multistageamplifier adjusted in accordance with the adjusted distributed gaincontrol signal, the determining whether the output power is within thedesired output power range, and the adjusting the distributed gaincontrol signal until the output power is within the desired output powerrange.
 4. The transmitter of claim 1, wherein the control module furthercomprises: processing module; and memory operably coupled to theprocessing module, wherein the memory includes operational instructionsthat cause the processing module to: generate a series of varying powerlevel test signals to test linearity of the programmable multistagepower amplifier; sequentially provide the series of varying power leveltest signals to up-conversion module, wherein the up-conversion moduleproduces a series of RF test signals based on the series of varyingpower level test signals, wherein the programmable multistage amplifieramplifies the series of RF test signals to produce a series of outboundRF test signals; determine output power for each of the series ofoutbound RF test signals; determine linearity of the programmablemultistage amplifier based on the output power of the series of outboundRF test signals; determine whether the linearity of the programmablemultistage amplifier is within a desired linearity range; when thelinearity of the programmable multistage amplifier is not within adesired linearity range, adjust the distributed gain control signal toproduce an adjusted distributed gain control signal; and repeat thesequentially providing of the series of varying power level test signalsto up-conversion module, the determining the output power for each ofthe series of outbound RF test signals with gain of the programmablemultistage amplifier adjusted in accordance with the adjusteddistributed gain control signal, the determining the linearity of theprogrammable multistage amplifier, the determining whether the linearityof the programmable multistage amplifier is within a desired linearityrange, and the adjusting the distributed gain control signal until thelinearity is within the desired linearity range.
 5. The transmitter ofclaim 1, wherein the control module further comprises: processingmodule; and memory operably coupled to the processing module, whereinthe memory includes operational instructions that cause the processingmodule to: generate a test signal to test for noise level of theprogrammable multistage amplifier; provide an I component and a Qcomponent of the test signal to the up-conversion module, wherein theup-conversion module produces an RF test signal that is amplified by theprogrammable multistage amplifier to produce an outbound RF test signal;determine noise level of the outbound RF test signal; determine whetherthe noise level of the outbound RF test signal is below a desired noiselevel; when the noise level of the outbound RF test signal is not belowthe desired noise, adjust the distributed gain control signal to producean adjusted distributed gain control signal; and repeat the providingthe I and Q components of the test signal, the determining the noiselevel of the outbound RF test signal with gain of the programmablemultistage amplifier adjusted in accordance with the adjusteddistributed gain control signal, the determining whether the noise levelis below the desired noise level, and the adjusting the distributed gaincontrol signal until the noise level is below the desired noise level.6. The transmitter of claim 5, wherein the test signal further comprisesone of: a null signal; and a signal having a known power level, whereinthe determining the noise level is based on a determined signal to noiseratio.
 7. The transmitter of claim 1, wherein the control module furthercomprises: processing module; and memory operably coupled to theprocessing module, wherein the memory includes operational instructionsthat cause the processing module to: determine a first optimal settingfor the distributed gain control signal such that a noise level of theprogrammable multistage amplifier is below a desired noise level;determine a second optimal setting for the distributed gain controlsignal such that output power of the programmable multistage amplifieris within a desired output power range; determine a third optimalsetting for the distributed gain control signal such that linearity ofthe programmable multistage amplifier is within a desired linearityrange; determine whether the linearity of the programmable multistageamplifier is within the desired linearity range, the output power of theprogrammable multistage amplifier is within the desired output powerrange, and the noise level of the multistage amplifier is below thedesired noise level for each of the first, second, and third optimalsettings for the distributed gain control signal; and when one or moreof the linearity, the output power, and the noise level of themultistage programmable amplifier is not within the desired linearityrange, the desired output power range, and below the desired noiselevel, respectively, for one or more of the first, second, and thirdoptimal settings, adjust the distributed gain control signal based onprioritization of the output power, the noise level, and the linearity.8. A radio comprises: receiver operably coupled to convert an inbound RFsignal into an I component of an inbound low intermediate frequency (IF)signal and a Q component of the low IF signal based on an I component ofa receiver local oscillation and a Q component of the receiver localoscillation; and transmitter that includes: up-conversion moduleoperably coupled to produce a radio frequency (RF) signal from an Icomponent of a low intermediate frequency (IF) signal, Q component ofthe low IF signal, an I component of a local oscillation, and a Qcomponent of a local oscillation; programmable multistage amplifieroperably coupled to amplify, based on a distributed gain control signal,the RF signal to produce an outbound RF signal; and control moduleoperably coupled to generate the distribute gain control signal based onan optimization of at least one of: power level, noise factor, andlinearity of the programmable multistage amplifier.
 9. The radio ofclaim 8, wherein the programmable multistage amplifier comprises: firstprogrammable amplifier operably coupled to produce an amplified RFsignal by amplifying the RF signal in accordance with a first gaincontrol signal of the distributed gain control signal; and secondprogrammable amplifier operably coupled to produce the outbound RFsignal by amplifying the amplified RF signal in accordance with a secondgain control signal of the distributed gain control signal.
 10. Theradio of claim 8, wherein the control module further comprises:processing module; and memory operably coupled to the processing module,wherein the memory includes operational instructions that cause theprocessing module to: generate a test signal to test for a desired powerlevel setting of the programmable multistage amplifier; provide an Icomponent and a Q component of the test signal to the up-conversionmodule, wherein the up-conversion module produces an RF test signal thatis amplified by the programmable multistage amplifier to produce anoutbound RF test signal; determine output power of the outbound RF testsignal; determine whether the output power of the outbound RF testsignal is within a desired output power range; when the output power ofthe outbound RF test signal is not within the desired output powerrange, adjust the distributed gain control signal to produce an adjusteddistributed gain control signal; and repeat the providing the I and Qcomponents of the test signal, the determining the output power of theoutbound RF test signal with gain of the programmable multistageamplifier adjusted in accordance with the adjusted distributed gaincontrol signal, the determining whether the output power is within thedesired output power range, and the adjusting the distributed gaincontrol signal until the output power is within the desired output powerrange.
 11. The radio of claim 8, wherein the control module furthercomprises: processing module; and memory operably coupled to theprocessing module, wherein the memory includes operational instructionsthat cause the processing module to: generate a series of varying powerlevel test signals to test linearity of the programmable multistagepower amplifier; sequentially provide the series of varying power leveltest signals to up-conversion module, wherein the up-conversion moduleproduces a series of RF test signals based on the series of varyingpower level test signals, wherein the programmable multistage amplifieramplifies the series of RF test signals to produce a series of outboundRF test signals; determine output power for each of the series ofoutbound RF test signals; determine linearity of the programmablemultistage amplifier based on the output power of the series of outboundRF test signals; determine whether the linearity of the programmablemultistage amplifier is within a desired linearity range; when thelinearity of the programmable multistage amplifier is not within adesired linearity range, adjust the distributed gain control signal toproduce an adjusted distributed gain control signal; and repeat thesequentially providing of the series of varying power level test signalsto up-conversion module, the determining the output power for each ofthe series of outbound RF test signals with gain of the programmablemultistage amplifier adjusted in accordance with the adjusteddistributed gain control signal, the determining the linearity of theprogrammable multistage amplifier, the determining whether the linearityof the programmable multistage amplifier is within a desired linearityrange, and the adjusting the distributed gain control signal until thelinearity is within the desired linearity range.
 12. The radio of claim8, wherein the control module further comprises: processing module; andmemory operably coupled to the processing module, wherein the memoryincludes operational instructions that cause the processing module to:generate a test signal to test for noise level of the programmablemultistage amplifier; provide an I component and a Q component of thetest signal to the up-conversion module, wherein the up-conversionmodule produces an RF test signal that is amplified by the programmablemultistage amplifier to produce an outbound RF test signal; determinenoise level of the outbound RF test signal; determine whether the noiselevel of the outbound RF test signal is below a desired noise level;when the noise level of the outbound RF test signal is not below thedesired noise, adjust the distributed gain control signal to produce anadjusted distributed gain control signal; and repeat the providing the Iand Q components of the test signal, the determining the noise level ofthe outbound RF test signal with gain of the programmable multistageamplifier adjusted in accordance with the adjusted distributed gaincontrol signal, the determining whether the noise level is below thedesired noise level, and the adjusting the distributed gain controlsignal until the noise level is below the desired noise level.
 13. Theradio of claim 12, wherein the test signal further comprises one of: anull signal; and a signal having a known power level, wherein thedetermining the noise level is based on a determined signal to noiseratio.
 14. The radio of claim 8, wherein the control module furthercomprises: processing module; and memory operably coupled to theprocessing module, wherein the memory includes operational instructionsthat cause the processing module to: determine a first optimal settingfor the distributed gain control signal such that a noise level of theprogrammable multistage amplifier is below a desired noise level;determine a second optimal setting for the distributed gain controlsignal such that output power of the programmable multistage amplifieris within a desired output power range; determine a third optimalsetting for the distributed gain control signal such that linearity ofthe programmable multistage amplifier is within a desired linearityrange; determine whether the linearity of the programmable multistageamplifier is within the desired linearity range, the output power of theprogrammable multistage amplifier is within the desired output powerrange, and the noise level of the multistage amplifier is below thedesired noise level for each of the first, second, and third optimalsettings for the distributed gain control signal; and when one or moreof the linearity, the output power, and the noise level of themultistage programmable amplifier is not within the desired linearityrange, the desired output power range, and below the desired noiselevel, respectively, for one or more of the first, second, and thirdoptimal settings, adjust the distributed gain control signal based onprioritization of the output power, the noise level, and the linearity.15. A programmable multistage amplifier comprises: first programmableamplifier operably coupled to produce an amplified signal by amplifyingan input signal in accordance with a first gain control signal; secondprogrammable amplifier operably coupled to produce an outbound signal byamplifying the amplified signal in accordance with a second gain controlsignal; and control module operably coupled to generate the first andsecond gain control signals based on an optimization of at least one of:power level, noise factor, and linearity of the programmable multistageamplifier.
 16. The programmable multistage amplifier of claim 15,wherein the control module further comprises: processing module; andmemory operably coupled to the processing module, wherein the memoryincludes operational instructions that cause the processing module to:generate a test signal to test for a desired power level setting of theprogrammable multistage amplifier; provide the test signal to the firstprogrammable amplifier such that the first and second programmableamplifiers amplify the test signal to produce an outbound test signal;determine output power of the outbound test signal; determine whetherthe output power of the outbound test signal is within a desired outputpower range; when the output power of the outbound test signal is notwithin the desired output power range, adjust at least one of the firstand second gain control signals to produce at least one adjusted gaincontrol signal; and repeat the providing of the test signal, thedetermining the output power of the outbound test signal with gain ofthe programmable multistage amplifier adjusted in accordance with the atleast one adjusted gain control signal, the determining whether theoutput power is within the desired output power range, and the adjustingof the at least one of the first and second gain control signals untilthe output power is within the desired output power range.
 17. Theprogrammable multistage amplifier of claim 15, wherein the controlmodule further comprises: processing module; and memory operably coupledto the processing module, wherein the memory includes operationalinstructions that cause the processing module to: generate a series ofvarying power level test signals to test linearity of the programmablemultistage amplifier; sequentially provide the series of varying powerlevel test signals to first programmable amplifier such that the firstand second programmable amplifiers amplify the series of test signals toproduce a series of outbound test signals; determine output power foreach of the series of outbound test signals; determine linearity of theprogrammable multistage amplifier based on the output power of theseries of outbound test signals; determine whether the linearity of theprogrammable multistage amplifier is within a desired linearity range;when the linearity of the programmable multistage amplifier is notwithin a desired linearity range, adjust at least one of the first andsecond gain control signals to produce at least one adjusted gaincontrol signal; and repeat the sequentially providing of the series ofvarying power level test signals to first programmable amplifier, thedetermining the output power for each of the series of outbound testsignals with gain of the programmable multistage amplifier adjusted inaccordance with the at lest one adjusted gain control signal, thedetermining the linearity of the programmable multistage amplifier, thedetermining whether the linearity of the programmable multistageamplifier is within a desired linearity range, and the adjusting of theat least one of the first and second gain control signals until thelinearity is within the desired linearity range.
 18. The programmablemultistage amplifier of claim 15, wherein the control module furthercomprises: processing module; and memory operably coupled to theprocessing module, wherein the memory includes operational instructionsthat cause the processing module to: generate a test signal to test fornoise level of the programmable multistage amplifier; provide the testsignal to the first programmable amplifier such the programmablemultistage amplifier produces an outbound test signal; determine noiselevel of the outbound test signal; determine whether the noise level ofthe outbound test signal is below a desired noise level; when the noiselevel of the outbound test signal is not below the desired noise, adjustat least one of the first and second gain control signals to produce atleast one adjusted gain control signal; and repeat the providing of thetest signal, the determining the noise level of the outbound test signalwith gain of the programmable multistage amplifier adjusted inaccordance with the at least one adjusted gain control signal, thedetermining whether the noise level is below the desired noise level,and the adjusting the at least one of the first and second gain controlsignals until the noise level is below the desired noise level.
 19. Theprogrammable multistage amplifier of claim 18, wherein the test signalfurther comprises one of: a null signal; and a signal having a knownpower level, wherein the determining the noise level is based on adetermined signal to noise ratio.
 20. The programmable multistageamplifier of claim 15, wherein the control module further comprises:processing module; and memory operably coupled to the processing module,wherein the memory includes operational instructions that cause theprocessing module to: determine a first optimal setting for the firstand second gain control signals such that a noise level of theprogrammable multistage amplifier is below a desired noise level;determine a second optimal setting for the first and second gain controlsignals such that output power of the programmable multistage amplifieris within a desired output power range; determine a third optimalsetting for the first and second gain control signals such thatlinearity of the programmable multistage amplifier is within a desiredlinearity range; determine whether the linearity of the programmablemultistage amplifier is within the desired linearity range, the outputpower of the programmable multistage amplifier is within the desiredoutput power range, and the noise level of the multistage amplifier isbelow the desired noise level for each of the first, second, and thirdoptimal settings for the distributed gain control signal; and when oneor more of the linearity, the output power, and the noise level of themultistage programmable amplifier is not within the desired linearityrange, the desired output power range, and below the desired noiselevel, respectively, for one or more of the first, second, and thirdoptimal settings, adjust at least one of the first and second gaincontrol signals based on prioritization of the output power, the noiselevel, and the linearity.